title: Co-residence patterns in hunter-gatherer societies show unique human social structure.
abstract: Contemporary humans exhibit spectacular biological success derived from cumulative culture and cooperation. The origins of these traits may be related to our ancestral group structure. Because humans lived as foragers for 95% of our species' history, we analyzed co-residence patterns among 32 present-day foraging societies (total n = 5067 individuals, mean experienced band size = 28.2 adults). We found that hunter-gatherers display a unique social structure where (i) either sex may disperse or remain in their natal group, (ii) adult brothers and sisters often co-reside, and (iii) most individuals in residential groups are genetically unrelated. These patterns produce large interaction networks of unrelated adults and suggest that inclusive fitness cannot explain extensive cooperation in hunter-gatherer bands. However, large social networks may help to explain why humans evolved capacities for social learning that resulted in cumulative culture.
authors.affiliation: School of Human Evolution & Social Change, Arizona State University, Tempe, AZ 85287, USA. kim.hill@asu.edu
authors.forename: Kim R
authors.initials: KR
authors.lastname: Hill
authors.forename: Robert S
authors.initials: RS
authors.lastname: Walker
authors.forename: Miran
authors.initials: M
authors.lastname: Bozicević
authors.forename: James
authors.initials: J
authors.lastname: Eder
authors.forename: Thomas
authors.initials: T
authors.lastname: Headland
authors.forename: Barry
authors.initials: B
authors.lastname: Hewlett
authors.forename: A Magdalena
authors.initials: AM
authors.lastname: Hurtado
authors.forename: Frank
authors.initials: F
authors.lastname: Marlowe
authors.forename: Polly
authors.initials: P
authors.lastname: Wiessner
authors.forename: Brian
authors.initials: B
authors.lastname: Wood
mesh_terms: D000328:Adult; D003299:Cooperative Behavior; D003431:Cross-Cultural Comparison; D003468:Cultural Evolution; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D044382:Population Groups; D012111:Residence Characteristics; D012919:Social Behavior